Collapsible, lightweight bulk shipping container

ABSTRACT

A container is assembled from several panels generally comprised of one or more layers of relatively rigid stiffening material (such as corrugated cardboard) sandwiched between two layers of a strong, flexible material, such as woven polypropylene. These panels form four side wall assemblies and, in combination with a flexible bottom panel, form a self-supporting, generally cubic material receiving box. An integral closure assembly, including cover flap, front flap and side flaps, advantageously enable the container to conveniently and safely secure relatively large volumes of dense debris without spillage even when the fully laden container is dropped during handling. The container, when empty, may be collapsed for convenient storage.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to industrial containers, and more particularlyto collapsible, lightweight, free-standing containers designed fortransporting bulk material, such as hazardous solid waste, in the formof an aggregate or a slurry.

2. Background Information

Conventional bulk shipping containers generally use either a bag conceptor a rigid box concept. The bag type container tends to be lightweightand easily collapsed when empty into a small volume for easy storage andshipping. It is, however, difficult to load and unload because it lacksrigidity and thus will not support itself in an open orientation tofacilitate loading. Also it is difficult to handle mechanically, such aswith a fork lift, without puncturing the bag. The rigid box design, onthe other hand, has the rigidity necessary to facilitate loading, topermit stacking of loaded containers, and to allow easy handling withfork lifts and other mechanical devices. However, by their very nature,such containers are not collapsible and thus require large volume forstoring and shipping even when empty.

Recent attempts to overcome these difficulties are described in U.S.Pat. No. 5,323,922 (the '922 patent) issued to J. H. Lapoint, Jr., etal. which is hereby fully incorporated by reference herein. The '922patent discloses a collapsible shipping container constructed using sidewall assemblies made from a double layer of flexible material formedinto pockets into which stiffeners are inserted. These containers can becollapsed into a small volume for storage or shipping while empty. Theyare lightweight and rigid enough that they can be filled and dischargedeasily, can be stacked during shipment even when loaded, and generallywill not slump, tilt, or topple over during shipment. They also haveloop type handles so that they can be easily handled by mechanicalequipment like fork lifts without danger of breaching the containmentintegrity of the container.

A drawback of this approach, however, is that it utilizes a relativelycomplex closure assembly in order to provide the requisite structuralintegrity to resist spillage of the contents during handling. Thisclosure assembly includes a discrete cover piece, several overlappinglayers of flaps on the top of the container, and a relatively largenumber of flexible ties at spaced locations about the entire peripheryof the cover piece. The discrete or non-integral cover piece may becomeseparated from the rest of the container assembly and be lost. Multiplelayers of materials tend to increase the cost of manufacturing thecontainer. Moreover, the relatively large number of flexible ties in acomplex closure arrangement increases the time and labor costs of usingthe container in its eventual application. Moreover, the use of tiesabout the entire periphery of the cover generally requires access to allsides of the container to secure it. This lends to disadvantageouslyprevent one from placing several empty containers side by side forsimultaneous filling, or from otherwise placing a container in confinedlocations, i.e. against a wall, for filling.

Thus, a need exists for a bulk material container that has a simplifiedclosure assembly, substantially without any discrete or unattachedcomponents, and that may be sealed shut from one side thereof tosimplify its manufacture and use.

SUMMARY OF THE INVENTION

According to an embodiment of this invention, a collapsible containeradapted to receive bulk material therein, includes:

a plurality of wall portions, each of the plurality of wall portionsincluding a plurality of layers of flexible sheet material and asemi-rigid stiffener superposed therebetween;

a bottom portion including at least one layer of flexible sheet materialdisposed integrally with the plurality of wall portions, wherein thebottom portion and the plurality of wall portions define a materialreceiving cavity;

a flexible closure assembly disposed integrally with at least one of theplurality of wall portions, the flexible closure assembly adapted toselectively open and close the material receiving cavity;

wherein the collapsible container is a unitary device adapted for beingalternately collapsed for storage and erected to a self-supportingconfiguration for receipt and containment of the bulk material.

The above and other features and advantages of this invention will bemore readily apparent from a reading of the following detaileddescription of various aspects of the invention taken in conjunctionwith the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a partially exploded diagrammatic perspective view, partiallybroken away, and in section, of a container of the prior art, in anopened condition, ready for loading.

FIG. 2 is a partially exploded, diagrammatic perspective view of anembodiment of the present invention in an opened or erected condition,ready for loading.

FIG. 3 is an enlarged, perspective, fragmentary, cutaway view at thelocation designated by 3 in FIG. 2.

FIG. 4 is a perspective, diagrammatic view of the container of FIG. 2,during a step in the process of closing the container, in which a firstside flap is folded over the container.

FIG. 5 is a view similar to that of FIG. 4, of another step in theclosure process of the present invention, in which a second side flap isfolded over the top and tied to the first side flap.

FIG. 6 is a perspective, diagrammatic view of the container of FIGS. 2-5in its closed position ready for shipment.

FIGS. 7, 8, and 9 are diagrammatic, cross-sectional plan views of thecontainer of FIG. 2, during steps in the process of folding it into itscollapsed storage position.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring to the figures set forth in the accompanying Drawings, theillustrative embodiments of the present invention will be described indetail hereinbelow. For clarity of exposition, like features shown inthe accompanying Drawings shall be indicated with like referencenumerals and similar features as shown in alternate embodiments in theDrawings shall be indicated with similar reference numerals.

Briefly described, the subject invention comprises a container 10 (FIG.2) assembled from several panels generally comprised of one or morelayers of relatively rigid or semi-rigid stiffening material (such ascorrugated cardboard) sandwiched between two layers of a strong,flexible material, such as polypropylene. These panels form side wallassemblies 12, 14, 16, and 18, which, in combination with a flexiblebottom panel 20, form a self-supporting, generally cubic materialreceiving box. An integral closure assembly 21, including cover assemblyor cover flap 22, front flap 24 and side flaps 26, advantageouslyenables container 10 to conveniently and safely secure relatively largevolumes of dense debris without spillage even when the fully ladencontainer is dropped during handling. The container, when empty, may becollapsed for convenient storage.

As used herein, the term “bulk material” shall be defined as a quantityof either hazardous or non-hazardous material which tends to bedimensionally unstable, i.e. liquid material or a flowable solid suchas, for example, sand, soil, debris, plastic or polymeric granules,beads, pills, etc. One skilled in the art will recognize that polymericsheet materials of the type utilized in construction of the presentinvention tend to melt and harden about the periphery of a burn hole toform a hard annulus similar to a grommet. Thus, as used herein, the term“grommet” shall be defined to include both conventional grommets andburn holes.

Referring now to the drawings in detail, as shown in FIG. 1, a prior artcontainer 110 includes side wall assemblies 112, 114, 116, 118, a bottomwall 120, and a cover member 122. The wall assemblies are each comprisedof one or more layers of a relatively rigid stiffening panel 34sandwiched between two layers 36 and 38 of strong, flexible, material,such as woven polypropylene. The inner layer 38 of the side wallassemblies extends above the stiffening panels to form a component partof the closure, or inner cover flap 40. The outer layer 36 extends abovethe stiffening panels to form an outer closure flap 42 which is providedwith a spaced array of grommets or burn holes 30. The bottom wall 120 ispreferably formed of a double layer 36 and 38 of the same flexiblematerial of the side wall assemblies. Cover member 122 is substantiallythe same size as the bottom wall 120, and is provided with a spacedarray of grommets 130, each aligned with a respective grommet 30 of theside wall flaps.

The subject container is provided with tie down means 144 to be used tosecure the container to a pallet(not shown) during shipment, and withlifting loops 146 which allow the container to be gripped and lifted bymechanical means.

Referring now to FIG. 2, container 10 of the present invention has asubstantially cubic shape, having side wall assemblies 12, 14, 16, 18,and a bottom wall 20 fabricated substantially as set forth in theaforementioned '922 patent. Bottom wall 20 is formed by two or morelayers of preferably the same strong, flexible, preferably liquid-proofmaterial as the side assemblies but without a stiffening member. Thecontainer also includes tie down means 44 and lifting loops 46 which aresimilar in construction and use to those shown in FIG. 1. An integralbottom 20 is preferably fabricated from the same material as the sidewalls, without stiffening panel 34. Grommets 30 are disposed atpredetermined locations in side flaps 12 and 18 and in cover flap 22 toprovide a simple means of closure for the box, which will be discussedin greater detail hereinafter.

Integral closure assembly 21 includes cover assembly 22, front flap 24and side flaps 26. As shown, side wall assemblies 12 and 18 have flaps26 of equal size formed by extending the inner and outer layers offlexible material from the opening or mouth of the container to aterminal edge. Flaps 26 are preferably fabricated without a stiffeningmember disposed between the fabric layers. The two layers of flexiblematerial are, in a preferred embodiment, stitched together to form eachflap 26. Each flap 26 is sized so that it extends approximately half wayacross the top of the container 10 when folded inwardly to its closedposition, as will be discussed hereinafter with respect to FIG. 4. Eachflap 26 is further provided with two grommets 30 spaced apart generallyalong the terminal edge thereof so that when the flaps 26 are closedover the top of the container, they can each be fastened to acorresponding grommet in the opposite flap as will be described indetail hereinbelow. Flap 24 extends from front wall assembly 14 in asimilar manner as the side wall flaps 26. Flap 24, in a preferredembodiment, includes neither a stiffening member nor grommets. Coverassembly 22 extends from sidewall assembly 16 in substantially the samemanner in which side wall flaps 26 extend from side walls 12 and 18,preferably without a stiffening member. Cover assembly 22 is sized andshaped to extend across and substantially close the top of the containerand extend partially down the front wall as will be discussedhereinafter with respect to FIG. 6. Cover assembly 22 has a grommet 30disposed proximate each corner of the flap along the terminal edgethereof. Cover assembly 22 is sized so that, when folded over the top ofthe container 10, the two grommets 30 are disposed in engageableproximity to integral ties 28 for securing the top in place andpreferably in tension, as will be discussed in detail hereafter.

Any number of materials may be utilized for construction of flexiblelayers 36 and 38 of the present invention. The chosen material ispreferably UV and water resistant, to help ensure integrity of thecontainer when exposed to the environment and adverse weatherconditions. A preferred material, as discussed in the above-referenced'922 patent, is woven polypropylene chemically treated in a known mannerfor UV resistance and which also may be treated in a conventional mannerfor improved water resistance. The construction of the presentinvention, including the fabric panels and stiffening panels 34sandwiched therebetween, provides a lightweight and inexpensivecontainer that is alternately movable between collapsed storage anderected, self-supporting orientations. This construction, moreover,provides the present invention with requisite structural integrity forcontaining relatively large volumes of dense material, such as, forexample, earth or construction debris, etc.

Moreover, as shown in FIG. 2 a liner or bag 32 may be used in oneembodiment either to maintain the cleanliness of the container for reuseor to provide liquid-tight containment during shipment of a wet materialor slurry. Bag 32 may be fabricated from woven polypropylene,waterproofed woven polypropylene, polyethylene, high densitypolyethylene, NYLON® or combinations thereof. In a preferred embodiment,bag 32 may be fabricated from a flexible resilient material, such aswoven polypropylene to increase the structural rigidity of thecollapsible container.

Turning to FIG. 3, the construction of the wall assemblies issubstantially identical in that disclosed in the above-referenced '922patent, including stiffening member 34. Member 34 preferably includesrigid plastic, corrugated fiber board, or similar material, disposed inpockets formed by inner and outer layers 36 and 38. The pockets formedby the inner 38 and outer 36 layers of the flexible material are sewn orsimilarly sealed shut (not shown) during manufacture of the container tosecure the stiffeners within their respective wall portions.

FIGS. 4-6 disclose successive steps in the process of utilizing closureassembly 21 of the present invention. Referring now to FIG. 4, in apreferred embodiment, bag 32 is disposed within container 10 and thenfilled with material 50. The bag is cinched shut in a conventionalmanner as shown, using a flexible tie element 48. One side flap 26 isthen folded over the top or mouth of the container. A flexible tieelement 48 is then inserted through the grommets 30 thereof as shown.The flexible tie elements, as disclosed in the aforementioned '922patent, may be any one of many conventional one-way flexible tiesreadily available from several sources.

Referring to FIG. 5, a second side flap 27 is folded over the top of thecontainer 10. It is provided with a size predetermined so that itsterminal edge substantially meets the terminal edge of side flap 26.Each flexible tie element 48 may then pass through a respective grommet30 in side flap 27 and lightened to secure the side flaps under in placeand under tension as shown, when container 10 is filled with bulkmaterial.

FIG. 6 shows the container 10 in its fully closed arrangement. Frontflap 24 has been folded over the top of the container before moving thecover flap 22 into its closed position as shown. In this regard, coverflap 22 is folded over the top of container 10 and partially down thefront sidewall assembly 14 where grommets 30 disposed on oppositecorners of the terminal edge of the flap are adapted for engagement withties 28 disposed integrally on the container. As shown, integral ties 28are tied through the respective grommets 30 to maintain the cover flapin tension (when the container is substantially filled) as the finalclosure step. As mentioned hereinabove, only one edge of cover flap 22is provided with grommets 30 and integral ties 28 are disposed only on asingle wall 14. Advantageously, this simplifies fastening of cover flap22 and enables such fastening to be accomplished by a user having accessto only one side of the fully laden container 10. This aspect tends tofacilitate close packing of multiple containers for simultaneous orsequential filling, or use of container 10 in otherwise close quarters.

As shown in FIGS. 7-9, container 10, when empty, may be collapsed into arelatively small volume for storage or shipping. Referring now to FIG.7, in the first step of the process one corner, in this example thecorner between side walls 12 and 14, is moved toward the diagonallyopposite corner. The tolerances between the stiffeners 34 and the pocketformed by the inner 38 and outer 36 layers of flexible material permitcontainer 10 to be temporarily distorted into the configuration shown.FIG. 8 shows a subsequent step of the process wherein the containercross-section has reached an “L” shaped or nested configuration. In thisorientation, the two diagonally opposite corners fully brought togetherso that the walls 12 and 14 are disposed in parallel relation with walls16 and 18, respectively. FIG. 9 shows the completed configuration inwhich the container is collapsed upon itself wherein walls 12, 14, 16and 18 are all superposed in parallel orientation relative to oneanother to minimize its volume for shipping or storage.

Closure assembly 21 of container 10 as embodied in the present inventionis advantageously simpler, easier, and faster to use than prior artcontainers that utilize a discrete, rigid cover portion. Such simplicitytends to facilitate greater productivity for the user, for reducedcosts.

Another advantage of the present invention is that the container 10comprises a single integral assembly with no separate parts to becomelost or separated during shipping or storage of the empty containers. Inthis regard, container 10 may be collapsed without removing any of thestiffeners as illustrated in FIGS. 7-9.

A further advantage of the present invention is that the manufacturingcost of the container is reduced by twenty-five to thirty-five percentover prior art containers due to use of fewer parts, and less material.

Moreover, while the present invention offers the above-referencedadvantages, tests of embodiments of the invention fabricated from 6.5ounce woven polypropylene ranging in capacity from 0.9 to 1.4 cubicmeters, and including bag 32, have been shown to be capable of holdingup to 1350 kg of bulk material, while satisfying all test standardsneeded to obtain UN (United Nations) approval. These test standardsinclude drop, topple, stacking, top lift and tear tests. Embodiments ofthe present invention fabricated using 8 ounce woven polypropylene havebeen similarly tested and found to be capable of holding up to 3200 Kgof bulk material. The containers of the present invention have also beenfound to pass the following DOT (US Department of Transportation) 7ATYPE A tests: Free Drop, Water Spray, Compression, and Penetration; andthe following 49 CFR PART 178 tests: Drop Test, Topple Test, StackingTest, and Tear Test. The loaded containers may be stacked up to threedeep with no deterioration of the bottom container in the stack. Theloaded containers also may be dropped or toppled with substantially nodeformation of the container and no loss of contents. These results weresurprising in light of the relative simplicity of the closure assembly,including use of a flexible, rather than rigid cover, and securing thecover along only one edge thereof.

The foregoing description is intended primarily for purposes ofillustration. Although the invention has been shown and described withrespect to an exemplary embodiment thereof, it should be understood bythose skilled in the art that the foregoing and various other changes,omissions, and additions in the form and detail thereof may be madetherein without departing from the spirit and scope of the invention.

Having thus described the invention, what is claimed is:
 1. Acollapsible container adapted to receive bulk material therein, thecollapsible container comprising: a plurality of wall portions, each ofsaid plurality of wall portions including a plurality of layers offlexible sheet material and a semi-rigid stiffener superposedtherebetween; a bottom portion including at least one layer of flexiblesheet material disposed integrally with said plurality of wall portions,wherein said bottom portion and said plurality of wall portions define amaterial receiving cavity; a flexible closure assembly disposedintegrally with said plurality of wall portions, said flexible closureassembly adapted to selectively open and close the material receivingcavity, the flexible closure assembly comprising: a flexible coverextending integrally from one of said wall portions; a pair of sideflaps extending from opposite wall portions, said pair of flaps beingsized and shaped to extend towards one another for tensioned mutualengagement to substantially close the material receiving cavity; a frontflap extending from a wall portion disposed opposite said flexible coverand adapted for superimposed engagement with said pair of side flaps;cover securing means disposed integrally on one or more of saidplurality of wall portions; said flexible cover being sized and shapedfor being secured in tension by said cover securing means in superposedorientation with said mutually engaged pair of side flaps and said frontflap to secure the bulk material within said collapsible containerwherein said collapsible container is a unitary device adapted for beingalternately collapsed for storage and erected to a self-supportingconfiguration for receipt and containment of the bulk material.
 2. Thecollapsible container as set forth in claim 1, wherein said pair of sideflaps extend from opposite wall portions, terminating at terminal edgeshaving an array of grommets disposed thereon, wherein correspondinggrommets of each said array of grommets are adapted for being fastenedto one another for said tensioned mutual engagement.
 3. The collapsiblecontainer as set forth in claim 1, wherein said flexible cover isadapted for being engaged by said cover securing means along a singleedge thereof to enable a user to alternately engage and release saidflexible cover while having access to only one side of said collapsiblecontainer.
 4. The collapsible container as set forth in claim 3, furthercomprising an array of grommets disposed in spaced relation on aterminal edge of said flexible cover, said flexible cover securing meansincluding an array of flexible ties disposed in spaced relation on saidplurality of wall portions, wherein each of said array of flexible tiesis adapted for tensioned engagement with at least one grommet of saidarray of grommets to secure said flexible cover in said superposedorientation.
 5. The collapsible container as set forth in claim 4,wherein said flexible ties are only disposed on one of said plurality ofwall portions.
 6. The collapsible container as set forth in claim 1,wherein said layers of flexible sheet material comprise wovenpolyethylene.
 7. The collapsible container as set forth in claim 6,wherein said semi-rigid stiffener comprises corrugated cardboard.
 8. Thecollapsible container as set forth in claim 1, being adapted to containup to approximately 0.9 to 1.4 cubic meters of bulk material.
 9. Thecollapsible container as set forth in claim 8, being adapted to containup to approximately 3200 Kg of bulk material.
 10. The collapsiblecontainer as set forth in claim 1, further comprising a flexible lineradapted for disposition within said collapsible container.
 11. Thecollapsible container as set forth in claim 10, wherein said flexibleliner is fabricated from one of the materials selected from the groupconsisting of woven polypropylene, waterproofed woven polypropylene,polyethylene, high density polyethylene, NYLON® and combinationsthereof.
 12. The collapsible container as set forth in claim 10, whereinsaid flexible liner further comprises a substantially waterproof bagadapted to facilitate containment of wet bulk material.
 13. Thecollapsible container as set forth in claim 12, wherein said waterproofbag is sealable.
 14. A method of securing bulk material for storage ortransport, the method comprising the steps of: (a) providing acollapsible container having: i) a plurality of wall portions, each ofsaid plurality of wall portions including a plurality of layers offlexible sheet material and a semi-rigid stiffener superposed therebetween; ii) a bottom portion including at least one layer of flexiblesheet material disposed integrally with said plurality of wall portions,wherein the bottom portion and the plurality of wall portions define amaterial receiving cavity; iii) a flexible closure assembly disposedintegrally with at least one of said plurality of wall portions, saidflexible closure assembly adapted to selectively open and close thematerial receiving cavity, wherein the collapsible container is aunitary device adapted for being alternately collapsed for storage anderected to a self-supporting configuration for receipt and containmentof the bulk material; (b) opening the flexible closure assembly; (c)depositing the bulk material in the material receiving cavity; (d)extending a pair of flaps towards one another and mutually engaging thepair of flaps to substantially close the material receiving cavity; (e)extending a front flap in superimposed relation with the pair of flaps;(f) extending a cover in superposed relation with the pair of flaps andthe front flap ; (g)(f) securing the cover in said superposed relation.15. A collapsible container adapted to receive bulk material therein,the collapsible container comprising: (a) a plurality of wall portions,each of said plurality of wall portions including a plurality of layersof flexible sheet material and a semi-rigid stiffener superposedtherebetween; (b) a bottom portion including at least one layer offlexible sheet material disposed integrally with said plurality of wallportions, wherein said bottom portion and said plurality of wallportions define a material receiving cavity; (c) a flexible closureassembly disposed integrally with at least one of said plurality of wallportions, said flexible closure assembly adapted to selectively open andclose the material receiving cavity, said flexible closure assemblyincluding: (i) a flexible cover extending integrally from one of saidwall portions; (ii) a pair of side flaps extending from opposite wallportions and sized and shaped to extend towards one another fortensioned mutual engagement to substantially close the materialreceiving cavity when bulk material is disposed therein; (iii) a frontflap extending from a wall portion disposed opposite said flexible coverand adapted for superimposed engagement with said pair of side flaps;(iv) cover securing means disposed integrally on one or more of saidplurality of wall portions, said flexible cover sized and shaped forbeing secured in tension by said cover securing means in superposedorientation with said mutually engaged pair of side flaps and said frontflap to secure the bulk material within said collapsible container;wherein said collapsible container is a unitary device adapted for beingalternately collapsed for storage and erected to a self-supportingconfiguration for receipt and containment of the bulk material.